1. Technical Field
The present invention relates to a method of manufacturing semiconductor chips in which a semiconductor wafer is divided and diced into individual pieces.
2. Background Art
In a known method of manufacturing semiconductor chips by dividing and dicing a semiconductor wafer into individual pieces, the semiconductor wafer is mechanically divided by a blade of a dicer. For instance, mechanical dicing with use of DBG (Dicing Before Grinding) technique is disclosed in JP 2002-100588 A. In the DBG technique disclosed in JP 2002-100588 A, grooves are formed on an element formation surface (front surface) of a semiconductor wafer by a blade, followed by attachment of a protection tape on the front surface. Subsequently, a surface (backside surface) of the semiconductor wafer opposed to the front surface is ground until the grooves are exposed, so that the wafer is diced into individual semiconductor chips.
The DBG technique with use of the dicer, however, has following problems. Firstly, a constraint of thickness of the blade (at least on the order of 40 to 50 μm) imposes limitations on improvement in chip yield per semiconductor wafer. Further, because the semiconductor wafer attached on the thin protection tape is diced into the individual semiconductor chips, interference among adjoining semiconductor chips may cause chipping on corner parts (edges) thereof. Furthermore, handling ability therefor is deteriorated after the backside surface is ground, because handling is needed with the diced semiconductor chips attached on the thin protection tape.
In addition to the mechanical dicing with use of dicer, a method (plasma dicing) of manufacturing semiconductor chips is known in which a semiconductor wafer is divided and diced into individual pieces by plasma etching. A plasma dicing method disclosed in JP 2004-172364 A including formation of resist pattern on a backside surface of a semiconductor wafer after grinding for thinning is executed, followed by plasma etching of backside surface thereof so that the semiconductor wafer is divided and diced into individual pieces. Disclosed in JP 2004-95952 A is a method in which a semiconductor wafer is divided and diced into individual pieces by execution of both of a step of performing plasma etching after forming a resist pattern on front surface and a step of performing plasma etching after forming a resist pattern on backside surface, that is, by execution of plasma etching from both the surfaces.
Disclosed in JP H07-201784 A is a method including forming a resist pattern on a front surface so as to cover element formation regions and attaching a protection tape on a backside surface, thereafter dividing and dicing a semiconductor wafer into individual pieces from the front surface by a dicer, and reforming sections produced by the dicer by plasma processing from the front surface.
With respect to method of manufacturing semiconductor chips in which a semiconductor wafer is divided and diced into individual pieces, there are various demands including not only above-mentioned the chip yield per semiconductor wafer, reduction in chipping, and the handling ability but also as small number of times of attaching of protection tape and small number of processes of photolithography for forming a resist pattern. The above described known methods of manufacturing semiconductor chips with the DGB technique or plasma dicing of various types cannot satisfy all of such demands.
It is an object of the present invention to provide a method of manufacturing semiconductor chips superior in various properties including chip yield per semiconductor wafer, reduction in chipping, and handling ability.